As FIG. 1 shows, it is common in a network 10 for circuit switched units, such as SSP 12 and SCP 14, to be connected with an external (or stand alone) Intelligent Peripheral (IP), such as external IP 16. The existence of SSP 12 and SCP 14 denotes that the network 10 is an intelligent network (IN), meaning that advanced services are available to network subscribers who want them. In the intelligent network 10, the external IP 16 may be used to perform functions that are IN related, such as play announcement and collect user information (PACUI). All the resources in external IP can be shared with other SSP/switches in the network (not shown) as long as there are appropriate links between them.
As shown in FIG. 1, the existing way for SCP 14 to communicate with external IP 16 is through a direct INAP link 18 between SCP 14 and external IP 16. Such an arrangement is defined in both ITU (International Telecommunication Union) and ETSI (European Telecommunication Standards Institute) standards.
ITU and ETSI standards also generally define another arrangement for a SCP and an external IP in which there is not any direct communication link between a SCP and an external IP. All the messages between SCP and external IP, in this configuration, are then relayed by the SSP that connect to both SCP and the external IP. Such an arrangement is called the SSP Relay Configuration and the SSP of such an arrangement is called the Relay SSP. Other SSP/switches can access the external IP either through the link via the relay SSP or through the direct ISUP/Voice trunk with the external IP.
Although ITU and ETSI standards generally define the SSP Relay Configuration, there is currently no standard describing the exchange of messages between the external IP and the SCP in a SSP Relay Configuration network. Thus, there is a need in the art for a SSP Relay Configuration network that has functioning communications between an SCP and an external IP. There is also a need in the art for a method of communicating between a SCP and an external IP in a SSP Relay Configuration network.